Modern Trends in Aircraft Hydraulic System - Report Example

HЕ MОDЕRN TRЕNDS IN АIRСRАFT НYDRАULIС SYSTЕM Name Institution Date Introduction According to Faleiro & Herzog (2004), over the years the aviation technology have improved a great deal all in a effort to increases and improve the performance of the aircraft in terms of a myriad of aspects. Including efficiency, carrying capacity, reducing fuel consumption, as well as maintenance cost and in the overall reduction in aircraft accidents. Consequently, this has led to a lot of improvement on the several systems in an aircraft including those in the design stage as well as in the operating system. Particularly they include the hydraulic systems which in general power the aircraft, the electric system and the communication system among others. In an effort to improve performance there have developed a great need to reduce or even eliminate completely the weaknesses and the flaws associated with each system, a move which has been induced profoundly by the vast improvement in technological innovations. In this regard, this research work brings to the fore the trends in the aircraft hydraulic system which to a greater perspective are meant to counteract the systems weaknesses (Faleiro & Herzog, 2004). In an ant shell, the hydraulic system comprises of a basic hydraulic fluids and combination of pistons. The system aids the aircrafts movements and at the same time actuating landing gears, flaps, slats, as well as brakes and weapon bay particularly military aircraft. The system is also fundamental in large aircrafts for instance Boeing 787, in flight control, reversers, spoilers among other aspects. Over time, the hydraulics has been used extensively because efficiently transmits high pressure using just a small mass of hydraulic fluids as argued by (Abdel-Hafez, 2012). Equally, hydraulic systems are termed reliable given the incompressible nature of the hydraulic oils. Indeed, the hydraulic system is based on the Pascal’s Law, as we all know it (Faleiro & Herzog, 2004). Aircraft Hydraulic system poses several weaknesses which if given enough attention can lead to adverse effects on the aircraft particularly its performance and can even lead to fatal accidents. Firstly, the hydraulic fluids are heavy hence complicating the problem of weight reduction as pointed out by (Abdel-Hafez, 2012). Secondly, the system requires high maintenance cost including ensuring zero leakage system, non-contaminated oils through proper mixing followed by thorough filtration. Additionally, these create logistics problems and further increasing cost. Thirdly, the system usually requires massive space to be taken by the myriad hydraulic lines, pumps, filters among other details. Consequently, this adds on the weight and the space which are critical aspects in an aircraft where heavy weight poses a threat especially when in the air. Additionally, the challenges are complicated by the nature of hydraulic oils which is highly susceptible to inflammation hence creating more risk to fatal fire accidents (Faleiro & Herzog, 2004). Although pneumatic systems that use air as a hydraulic fluid in place of oils have been widely used to solve the weight problem posed by hydraulic oils, the leakage problems, and the maintenance cost have persisted in plaguing the conventional aircrafts as argued by (Faleiro & Herzog, 2004). In an effort to completely solve the problems solved by the hydraulic and pneumatic systems, serious progress in electric powered aircraft myriad systems has progressively been adopted. Faleiro & Herzog (2004), points out that there is an increased trend of electric system in the aircraft industry gradually replacing the hydraulic. As well as pneumatic system hence facilitating the realization of more comfort, improving the energetic efficiency as well as monitoring features. This latest innovation of technology is widely regarded as more Electric Aircraft, which simply means to drive all the aircraft subsystem by means of electric power (Faleiro & Herzog, 2004). According to Abdel-Hafez (2012), the idea of MEA was originally intended to enhance the military activities through reducing aircraft weight, better performance, lowering maintenance cost as well as higher and improved reliability. Progressively civil aircraft adopted the technological for instance B787/A380 and A340 developed by air bus. MEA strategy has several advantages over conventional strategy of mechanical, hydraulic system and pneumatic system. Firstly, it eliminates the hydraulic systems as a way of powering the aircraft and it is replaced by electric power such as in Joint Strike Fighter and the Boeing 7E7. In this regard, such faults such susceptibility to leakages, high cost of maintenance (repairing the leakages, filtering and maintenance of contamination free hydraulic oils); the aircraft space is increases while the weight a critical parameter of aircraft is reduced. Additionally, the introduction of an electric motor-driven pump in place of an engine bleed-system creates more efficiency and at the same time facilitate in the reduction of mechanism and complexity (Abdel-Hafez, 2012). The F/A-18 Hornet, for instance, was developed under MEA technology and it is said to be a reliable aircraft with extremely reduced weight and very low cost of maintenance (United State Navy, 2009). In fact, United State Navy (2009) noted that the aircraft could be repaired within a day and resumes its activities the following day with a lot of ease. E-Fan electric aircraft developed by Airbus Company is equally an exotic aircraft which been developed under MEA technology hence enhancing its activity (United State Navy, 2009). With the MEA survivability is of an aircraft is enhanced even with engine failure given the power availability enhanced by the windmill option facilitated by the power generator by use of its fan shaft. In this regard, this method guarantee increased the reliability of an aircraft as pointed out by (United State Navy, 2009) compared to the conventional systems. Further, MEA requires the use of the advanced magnetic bearing system and as such can creating an oil free as well as gear-free engine area an aspect that reduce weight and cooling of the engine among other merits. Indeed, MEA has revolutionized aircraft industry to a greater extent and has therefore facilitated in the creation of spacious aircraft. For instance, the A340 and the Boeing 787 Dream liner among others reduced and proper fuel consumption as well as re configurability. Equally, they have become easier to maintain and support and most importantly more reliability is highly achieved. These have developed due to massive innovations in more fault tolerant mechanism hence enhancing the generation of power, processing, as well as distribution and management of power (Abdel-Hafez, 2012). Following electro mechanic and electro hydrostatical actuation, there has been more progress in power electronics technology hence enhancing safety and efficiency of the aircraft systems. The decade of between 1940-1950 28Vdc was widely used as the electric power. Additionally, dc batteries usually accompanied the aircraft where it was preserved for loading during emergency occasions. Progressively, the dc technology evolved to ac power where power system in aircraft employed multi-voltage levels of dc was converted to A.C form. In latest power technology, power electronic converters including dc to dc choppers. D.C to A.C rectifiers and ac to dc inverters have proved to be essential in the latest modern aircraft as observed by (Faleiro & Herzog, 2004). In this regard, the multi-converter power electronic systems have been observed as the main structure of MEA. As pointed by Faleiro & Herzog (2004), modern aircraft has developed into an intricate electric power system consisting of mixed voltages structures consisting of four types of voltage: 115Vac, 235Vac, 270Vdc and 28Vd. These electrical power generation methods have been categorized six schemes and consequently the distribution of the power proceeds after every scheme. Firstly power can be generated using constant frequency system (CF) also known as Integrated Drive Generator (IDG). In this, an electric generator is used following the use of the electric speed converter. As such, the latter (The speed converter) facilitated constant speed for the former (electric generator) hence regular rate to the productivity. The presence of the generator is the most shortcoming of this method since it is usually the gearbox that is relatively heavy hence adding on to the weight of the aircraft. Moreover, the reliability of the gearbox happens to be another problem hence making this process of power generation more costly, undependable as well as being cumbersome (Faleiro & Herzog, 2004, & Abdel-Hafez, 2012). The second method is frequently applied in military aircraft though it is also used sparingly in civil aircraft, for instance, the B767-400 from United Airlines. It is widely referred to as variable speed constant frequency system (VSCF) with DC link where a static electric converters and as well as dc generators where regular frequency AC voltage is achieved. Compared to the IDG method, this method is quite reliable simpler, and weight is considerably reduced. A third method is quite similar to the VSCF with DC link where in place of dc generator being used an a generator which is operated via the aircraft engine with rather varying speed. Further the power electronic converter converts the varying AC frequency power into AC power with regular amplitude. This method becomes relatively useful in commercial aircrafts that are heavy consumers of power and at the same, some conditions of operation may lead to reduction of power. This is because the method enhances the converter efficiency once the power reduces as argued by (Faleiro & Herzog, 2004). As they further indicated, F-18E/F from United States Navy is quit efficient and reliable and equally has lower maintenance cost. The fourth method which is more of an experiment commonly referred to as variable frequency having a frequency between the limits of 360-800 Hz as observed by (Abdel-Hafez, 2012). The VF method which is also known as wild frequency happens to be the latest power generation scheme. The power generator is embedded on the engine shaft directly a process that de-rates power take-off, as well as the connected gear box. As such, they are highly reduced in size and, on the other hand, the increment in reliability. Of all the electric powered generation of aircraft, VF is admirable in its small size low weight as well as highly reduced cost and volume. However, VF poses relatively high engine risk especially with the large amount of electric energy levels as argued by (Abdel-Hafez, 2012). Another shortcoming that manifest with VF are among others; the need of engine restructuring to accommodate the electric generators and the high heat energy will pose additional risk to the engine oil hence a heat exchange mechanism being very essential. Another fifth source of power is the auxiliary power unit commonly abbreviated as APU. This is that emanates from AC generators that are mainly operated by the core engines. This power usually drives the aircraft during the usual flight conditions. Further, the power equally drives the aircraft while in ground maintenance and also the entire engine starting process. According to Abdel-Fadil, Eid & Abdel-Salam (2013), APU can equally provide a backup electric power source in case of a generator failure in the usual aircraft functioning hence being very critical. Lack of enough or no electric power may be as a result of malfunctioning of generators, or even total APU malfunctioning induces Ram Air Turbines to generate or produce emergency electric power with DC output a seventh scheme. Power converters are essential for the RAM or fuel cells to optimally function in their interfacing aspects. Alternatively, batteries which usually operate in together with fuels cells given their dawdling chemical reactions can comfortably do provision of emergency powering of the systems. Lastly, power for maintenance and testing is fundamental to aircraft while operating for longer periods on the ground. As such is responsible for ground power unit which is similar to aircraft AC generators and usually has as the standard of three phase 200VAC 400Hz (Abdel-Fadil, Eid & Abdel-Salam, 2013). Conclusion The latest trend as discussed above is the More Electric Aircraft which emphasis on the replacement of aircraft hydraulic, pneumatic and mechanical systems which happens to have myriad of weaknesses such as leakages, heavy weight as well as high maintenance cost. In this regard, more benefit is constantly achieved which in overall leads to high performance, increased safety, reliability as well as the space. Complexity and weigh which would have increased for the conventional methods are highly reduced hence more space and as such translating to more passengers on board. These modern trends facilitated by the advancement in technology including electric power technology as well as the development of more raw materials hence facilitating more service to the humanity a natural goal of technological innovations. References Abdel-Fadil R., Eid A., & Abdel-Salam M., (2013). Electrical Distribution Power Systems of Modern Civil Aircrafts. 2nd International Conference on Energy Systems and Technologies 18 – 21 Feb. 2013, Cairo, Egypt. Pp 201-210 Abdel-Hafez A., (2012). Power Generation and Distribution System for a More Electric Aircraft. A Review. Journal of Recent Advances in Aircraft Technology.vol 13, Pg 289-305. Faleiro L, Herzog J., (2004). Integrated Equipment Systems For A More Electric Aircraft. Hydraulics and pneumatic. International Congress of The Aeronautical Sciences.Pp 1- 10 United State Navy, (2009). F/A-18 Hornet strike fighter. Retrieved on May 5, 2015 from http://www.navy.mil/navydata/fact_display.asp?cid=1100&tid=1200&ct=1 Read More

Although pneumatic systems that use air as a hydraulic fluid in place of oils have been widely used to solve the weight problem posed by hydraulic oils, the leakage problems, and the maintenance cost have persisted in plaguing the conventional aircrafts as argued by (Faleiro & Herzog, 2004). In an effort to completely solve the problems solved by the hydraulic and pneumatic systems, serious progress in electric powered aircraft myriad systems has progressively been adopted. Faleiro & Herzog (2004), points out that there is an increased trend of electric system in the aircraft industry gradually replacing the hydraulic.

As well as pneumatic system hence facilitating the realization of more comfort, improving the energetic efficiency as well as monitoring features. This latest innovation of technology is widely regarded as more Electric Aircraft, which simply means to drive all the aircraft subsystem by means of electric power (Faleiro & Herzog, 2004). According to Abdel-Hafez (2012), the idea of MEA was originally intended to enhance the military activities through reducing aircraft weight, better performance, lowering maintenance cost as well as higher and improved reliability.

Progressively civil aircraft adopted the technological for instance B787/A380 and A340 developed by air bus. MEA strategy has several advantages over conventional strategy of mechanical, hydraulic system and pneumatic system. Firstly, it eliminates the hydraulic systems as a way of powering the aircraft and it is replaced by electric power such as in Joint Strike Fighter and the Boeing 7E7. In this regard, such faults such susceptibility to leakages, high cost of maintenance (repairing the leakages, filtering and maintenance of contamination free hydraulic oils); the aircraft space is increases while the weight a critical parameter of aircraft is reduced.

Additionally, the introduction of an electric motor-driven pump in place of an engine bleed-system creates more efficiency and at the same time facilitate in the reduction of mechanism and complexity (Abdel-Hafez, 2012). The F/A-18 Hornet, for instance, was developed under MEA technology and it is said to be a reliable aircraft with extremely reduced weight and very low cost of maintenance (United State Navy, 2009). In fact, United State Navy (2009) noted that the aircraft could be repaired within a day and resumes its activities the following day with a lot of ease.

E-Fan electric aircraft developed by Airbus Company is equally an exotic aircraft which been developed under MEA technology hence enhancing its activity (United State Navy, 2009). With the MEA survivability is of an aircraft is enhanced even with engine failure given the power availability enhanced by the windmill option facilitated by the power generator by use of its fan shaft. In this regard, this method guarantee increased the reliability of an aircraft as pointed out by (United State Navy, 2009) compared to the conventional systems.

Further, MEA requires the use of the advanced magnetic bearing system and as such can creating an oil free as well as gear-free engine area an aspect that reduce weight and cooling of the engine among other merits. Indeed, MEA has revolutionized aircraft industry to a greater extent and has therefore facilitated in the creation of spacious aircraft. For instance, the A340 and the Boeing 787 Dream liner among others reduced and proper fuel consumption as well as re configurability. Equally, they have become easier to maintain and support and most importantly more reliability is highly achieved.

These have developed due to massive innovations in more fault tolerant mechanism hence enhancing the generation of power, processing, as well as distribution and management of power (Abdel-Hafez, 2012). Following electro mechanic and electro hydrostatical actuation, there has been more progress in power electronics technology hence enhancing safety and efficiency of the aircraft systems. The decade of between 1940-1950 28Vdc was widely used as the electric power.

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